Electromagnetic switch



y R H. SULLIVAN 2,003,021

ELECTROMAGNETIC SWITCH Original Filed May 29, 1930 2 Sheets-Sheet 1 z I 1 1 1 r ATTORNEYS y 1935. R. H. SULLIVAN 2,003,021

ELECTROMAGNETIC SWITCH Original Filed May 29, 1930 ;2 Sheets-Sheet 2 .I/ W e L m 10/2 [OZ I fvuLmvo/v INVENTOR Y 1 w om Patented May 28, 1935 UNITED STATES PATENT OFFICE ELECTROMAGNETIC SWITCH 7 Original application May 29, 1930, Serial No. 457,112. Divided and this application August 13, 1931, Serial No. 556,831

3 Claims.

This invention relates to apparatus for controlling an electrical system, and more particularly to an electromagnetically controlled switching or relay device.

One of the objects of the invention is to provide a switch for purposes such as automatically controlling a circuit including a battery and a generator for charging the battery, which switch operates at a substantially predetermined voltage regardless of temperature change.

A further object of this invention is to provide a switch or relay device in which there is less tendency for the contacts to stick together.

This application is a division of application Serial No. 457,112, filed May 29, 1930'which has been issued as Patent No. 1,968,971.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is a sectional view taken substantially on the line of Fig. 2, and looking in the direction of the arrows.

Fig. 2 is a fragmentary top view of the switch or relay device shown in Fig. 1.

Fig. 3 is an exploded view of the switch or relay 1 device shown in Figs. 1 and 2.

The switch or relay device comprises chiefly three subassemblies,-a base subassembly, a magnet subass'embly and an armature subassembly. The magnet'subassembly comprises an assembly of electromagnets of the switch, this subassembly being attached to the base subassembly by riveting thereto the central cores of the electromagnets. The armature subassembly is then attached'to the magnet subassembly. The base subassembly comprises a base frame 20 having 40 legs 2| by which the base may be attached to a support, such as the cylindrical frame of the dynamo-electric machine. An insulating plate 23 is secured to the upper side of the base frame 20 by rivets such as 22, or other suitable fastening means. Plate 23 has holes 26 in alignment with the larger holes 21 in the base 20. These holes receive magnet cores, to be described later. On the underside of .the base 20, are located two nonconducting plates 28 having holes 29 in alignment with the holes 26 through the plate 23, and substantially the same size as the latter holes. The plates 28, together with metallic terminal plates 3| and 32, are attached to the base plate by rivets such as 35, or other suitable fastening means, fastened through aligned holes in the The magnet subassembly comprises an assembly of two magnet cores and an armature hinge platesubassembly, magnet windings and insulating plates placed upon the cores adjacent the ends of the windings. This subassembly comprises cores 40 and 4|, the upper ends of which are attached to a subassembly including an armature hinge and stop plate 42 having ears 43 provided with holes 44 that are preferably threaded, and having a stop lug 45 that is preferably sub stantially T-shaped. The hinge plate 42 is preferably secured to a magnetic shunt plate 41,

the magnetic permeability of which varies with temperature. The plate 41 is provided with two large holes 48 -which receive magnetizable washers 49, which washers are preferably secured in their respective holes by staking, or by other suitable means. Upper reduced end portions 5| of the magnet cores 40 and 4| pass through aligned holes in the hinge plate 42 and washers 49, and are riveted over against the washers.

An insulating plate 12 is provided for assembling the switch with an adjacent unit, not shown, and this plate has holes .10 for receiving the cores 4!! and 4|. The plate also preferably has notches such as 13 and an oblong hole 74 therein. Following the assembling together of the armature hinge plate and the core subassembly, the

magnet coils 80 and 8|, previously wound upon' forms, are placed around the cores 40 and 4| respectively. In the particular form shown, before assembling the coil 80 upon the core 40, the form wound coil 82'is assembled upon the coil 80. Following this, an insulating plate 83 is placed upon the cores 40 and 4| to insulate the ends of the coils 80 and 8|, and to tie the lower end of the cores 40 and 4| together in proper spaced relation. Then a spring hooked plate 84 is assembled upon the projecting ends of the cores 40 and 4 This assembly of magnet cores, magnet coils, armature hinge plate, magnetic shunt and spring hooked plate is attached to The relay armature subassembly comprises a rigid armature plate I attached by rivets IOI, or other suitable fastening means, to an insulating plate I02, which plate is attached by rivets I03, or other suitable fastening means, to a flexible spring conductor I04. The flexible spring conductor I04 has a wire receiving hook I at one end, and carries at the other end a contact I06, which contact cooperates with a contact I 01 that is carried by the armature plate I00. The contact which is positive is preferably silver, and the contact which is negative is preferably tungsten. The spring conductor I04 carries a fiber bumper block I I0 having a shank I I I passing through a hole in the spring I04, and having a groove IIZ which receives a spring clip II3 which detachably secures the bumper block IIO to the spring I04. The contact. I06 is welded to the plate I08 having a shank I09 which passes through the spring I04 and is riveted over against a washer I09a located upon the upper side of the spring I04. magnetizable rivet H5 which prevents actual contact between the armature I00 and the pole pieces of the magnet that are provided by the upper ends of the cores 40 and 4|. rivets IOI secure to the armature I00 a leaf spring hinge plate H6 having apertured ears II1 through which screws II8 pass. The screws I I8 are threaded into the holes 44 in the ears 43 of the hinge bracket 42. When the armature subassembly is attached to the magnet subassembly in this manner, a spring I I9 is attached to the hook plate 42 and to a notched end I20 of the armature I00. This spring urges the armature I00 in a counter-clockwise direction as viewed in Fig. 1. Before attaching the armature I00 to the hinge plate 42, the T-shaped lug 45 is passed through an opening I2I in the armature I 00, and then the armature I00 is moved edgewise to locate the holes for the screws I I8 and to align those holes with the holes 44 and the bracket 42. When so moving the armature, the shank of the T-shaped lug 45 is located into an opening I22 that is smaller in width than the head of the lug 45. Therefore, the-head of the lug 45 operates to provide a stop that engages the upper surface of the armature I00 to limit movement of the armature away from the magnet, as eifected by the spring II 9. When the armature is attached to the hinge plate, the bumper block H0 is located above the lugv 45, and is normally spaced therefrom.

The magnetic shunt 41 preferably has a negative temperature coefiicient of magnetic permeability, and is preferably made of a special alloy of nickel and steel, so constituted that it will cause the relay to operate similarly, at substan-' tially a predetermined voltage, regardless of temperature. That is, the magnetic shunt is preferably so constituted that as the temperature increases, the permeability of the shunt 41 becomes lowered to tend to'cause more flux to link the armature and vice versa. This magnetic shunt 41 also preferably compensates for the increase of resistance in the windings of the electromagnets that is effected by an increase 1n temperature. When the voltage impressed upon the electromagnet coils 80 and 8| is in excess of a certain value, the armature I00 is attracted toward the cores 40 and 4| against the action of the spring II9 which normally holds the armature against the stop 45. As the armature I00 moves toward the cores 40 and 4|, the leaf spring conductor I 04 tends to follow the The armature I00 carries a non-,

Some of the armature until movement of that conductor is arrested by the bumper block IIO striking the stop 45. Further movement of the armature I00 toward the cores 40 and 4| effects the separation of the contacts I06 and I01. When the voltage decreases or is below a certain value, the armature and leaf spring conductor return to their normal positions.

As previously mentioned, in the particular switch shown, a winding 82 is provided which surrounds a portion of the outside of one of the electromagnets. In this particular switch, this winding 82 is preferably of relatively few turns of relatively coarse wire, and is connected in series with the contacts I06 and I01. The Winding 82 assists the windings 80 and 8I to separate the switch contacts. However, when the contacts are separated, the magnetic effect ofthe winding 82 is altered thereby. It is understood, however, that in many instances this additional winding 82 is not necessary to the operation of switch, and may be eliminated. One of the advantages of utilizing the coil such as 82 is that in case the contacts tend to stick together, coil 82 materially assists in opening the contacts.

The temperature compensating magnetic shunt is particularly desirable when the switch is utilized for the control of apparatus such as an automobile generator, and where wide variations in temperature are encountered. That is, in the control of an automobile generator, there are not only the variations in temperature that occur in different weather, but also the temperature depending upon that of the automobile engine. In

this particular application, it is very desirable to have the switch operate consistently in spite of the wide variations in temperature.

It has been found that a satisfactory alloy for making the magnetic shunts of the switch is one The bumper block I I 0 cooperates with the stop 45 to cause the blade I04 to bend about stop 45 as a fulcrum as the armature I00 moves toward the regulator magnet toseparate the contacts I06 and I01. Since the armature I 00, carrying contact- I01, bends about a fulcrum substantially removed from the fulcrum about which the blade I04, supporting contact I06, bends just before contact separation, contact I08 will teeter or rock upon the contact I01 before separation takes place. This rocking motion tends to allow the contacts to become separated easily, and minimizes sticking. While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is asfollows:

1. An electromagnetic switch comprising, in combination, a base; a pair of magnet cores insulatingly secured at one end to the base, and. having windings thereon; an armature hinge bracket secured to the other ends of the cores; an

armature carrying a contact and hingedly concured to the base intermediate the winding and base; and a spring connecting the spring bracket and armature.

2. An electromagnetic switch comprising, in combination, a base; a pair of magnet cores insulatingly secured at one end to the base, and having windings thereon, said cores being secured to the base by riveting the ends thereof; a spring bracket insulatingly secured to the base intermediate the winding and base; an armature hinge bracket and a temperature responsive magnetic shunt having corresponding apertures therethrough, through which the cores extend, said bracket and said shunt being secured to the cores by riveting the ends of the cores; an armature hingedly connected with the bracket and carrying a contact; a cooperating contact; a spring connected to the spring bracket and armature to bias the armature away from the cores; and a stop integral with the hinge bracket and extending through the armature to arrest motion of the contact in one direction.

3. An electromagnetic switch comprising, in combination, a base; a pair of magnet cores in- 3 sulatingly secured at one end to the base, and. having windings thereon, said cores being secured to the base by riveting the ends thereof; a spring bracket insulatingly secured to the base intermediate the winding and base; an armature hinge bracket and a temperature responsive magnetic shunt having corresponding apertures therethrough, through which the cores extend, said bracket and said shunt being secured to the cores by riveting the ends of the cores; an armature hingedly connected with the bracket and carrying a contact; a cooperating contact; a spring connected to the spring bracket and armature to bias the armature away from the cores; said windings being connected electrically to effect movement of said armature toward the cores against the biasing force of the spring, and said magnetic shunt efiecting a change in the flux linking said armature as the temperature changes; and a stop integral with the hinge 20 bracket and extending through the armature to arrest motion of the contact in one direction.

RAYMOND H. SULLIVAN. 

